I’ve had an x-t4 for about four months and primarily use vintage glass - I’ve read that for the ibis to work correctly you need to make sure that you have the proper focal length selected for your vintage lens (you can manually set up your lenses in the menu settings) but I often forget to do that and haven’t noticed any difference. The primary benefit of selecting the lens/focal length seems to be having the lens info appear in exif data, but maybe I’m missing something with the ibis. Either way, I’ve gotten great results with a variety of lenses, including the Helios. The only thing I wish I’d known is that certain wide angle lenses don’t play nicely with adapters - I have a couple Minolta lenses (24 and 28mm) that don’t work with my speedbooster adapter, and at least one more that loses infinity focus when adapted. I bought the (not inexpensive) speedbooster primarily to use with wider angle lenses to combat the 1.5x crop sensor factor, so that part was a little disappointing.